Microwave tumors ablation: Principles, clinical applications and review of preliminary experiences
ABSTRACT Local ablative techniques have been developed to enable local control of unresectable tumors. Ablation has been performed with several modalities including ethanol ablation, laser ablation, cryoablation, and radiofrequency ablation. Microwave technology is a new thermal ablation technique for different types of tumors, providing all the benefits of radiofrequency and substantial advantages. Microwave ablation has been applied to liver, lung, kidney and more rarely to bone, pancreas and adrenal glands. Preliminary works show that microwave ablation may be a viable alternative to other ablation techniques in selected patients. However further studies are necessary to confirm short- and long-term effectiveness of the methods and to compare it with other ablative techniques, especially RF.
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ABSTRACT: The standard treatment of small renal masses is partial nephrectomy, which has showed similar oncologic results when compared with radical nephrectomy. Recently, ablative techniques, including radiofrequency and cryotherapy ablation, has been developed, with the purpose of minimizing adverse effects of standard surgical excision. In this article we review the technique of radiofrequency ablation. For this review we conducted a search in the Medline database using the terms "renal radiofrequency ablation". The different currently marketed systems for the delivery of radiofrequency energy are examined. The different techniques of delivery (open, laparoscopic and percutaneous) are described; we observe a trend towards the use of the percutaneous method. Among the published clinical studies there are series of patients with midterm follow-up (3 years) that show oncologic outcomes similar to traditional resection techniques, with fewer complications. Renal tumor radiofrequency ablation has proved an effective therapy with minimal complications. However, it should be used only in selected patients until longer follow-up studies are available.Actas urologicas españolas 02/2009; 33(1):35-42. DOI:10.1007/978-3-540-87597-0_23 · 1.15 Impact Factor
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ABSTRACT: In this study, we attempted to implement parametric perfusion imaging to quantify blood perfusion based on modified low-cost ultrasound platform. A novel ultrasound contrast-specific imaging method called pulse-inversion harmonic sum-squared-differences (PIHSSD) was proposed for improving the sensitivity for detecting contrast agents and the accuracy of parametric perfusion imaging, which combined pulse-inversion harmonic (PIH) with pulse-inversion sum-squared-differences (PISSD) threshold-based decision. PIHSSD method just involved simple operations including addition and multiplication and was easy to realize. The sequences of contrast images without logarithmic compression were used to acquire time intensity curves (TICs) from numerous equal-sized regions-of-interest (ROI) covering the entire image plane. Parametric perfusion images were obtained based on the parameters extracted from the TICs, including peak value (PV), area under curve (AUC), mean transit time (MTT), peak value time (PVT), peak width (PW) and climbing rate (CR). Flow phantom was used for validation and the results suggested that PIHSSD method provided 9.6 to 20.3 dB higher contrast-to-tissue ratio (CTR) than PIH method. The results of the experiments of rabbit kidney also showed that the CTR of PIHSSD images was higher than that of PIH images, and the parametric perfusion images based on PIHSSD method provided more accurate quantification of blood perfusion compared with those based on PIH and PISSD methods. It demonstrated that the parametric perfusion imaging achieved good performance though implemented on low-cost ultrasound platform. (E-mail: firstname.lastname@example.org).Ultrasound in medicine & biology 11/2009; 36(1):130-44. DOI:10.1016/j.ultrasmedbio.2009.09.002 · 2.10 Impact Factor